Fast relaxing red and near-IR switchable azobenzenes with chalcogen and halogen substituents: periodic trends, tuneable thermal half-lives and chalcogen bonding

Abstract

Molecular photoswitches operating in the red to near-IR region with controllable thermal relaxation rates are attractive components for photo-regulating biological processes. Herein, we report the synthesis of red-shifted azobenzenes functionalised...

Red-light photoswitching of indigos in polymer thin films

“…[31][32][33] Hence, extensive research has been carried out to red-shi the isomerisation wavelengths, ultimately aiming for the therapeutic window above 650 nm. 9,12,34,35 To this end, progress has been made by (i) changing the electronic properties of conventional photoswitches such as azobenzenes through structural changes, [36][37][38][39][40][41] (ii) designing new photoswitchable scaffolds and structures that intrinsically absorb low-energy light, 25,[42][43][44] and (iii) exploiting indirect isomerisation using photocatalysts. [45][46][47] Yet, the vast majority of these investigations has been restricted to solution, and switching with red or near-infrared light in solid matrices has remained largely unexplored.…”

Twelve-membered ring photoswitches with excellentZ→Econversion under ambient light

“…17 Various substitution patterns with both electron withdrawing and donating substituents have been demonstrated to be effective at fine tuning the photophysical properties of an azobenzene switch. 18…”

“…17 Various substitution patterns with both electron withdrawing and donating substituents have been demonstrated to be effective at fine tuning the photophysical properties of an azobenzene switch. 18 An intriguing approach incorporates an azo-bridge into cyclic molecules of various ring sizes, 2,[19][20][21][22][23] resulting in extended thermal half-lives, improved band separations, and red shifted excitation wavelengths. Additionally, swapped thermal stability of the isomers is observed in the case of small ring sizes of seven (diazepines) 24 or eight atoms (diazocines).…”

Photoresponsive Diarylethene‐Containing Polymers: Recent Advances and Future Challenges

“…However, AZO and SP are T-type photochromic molecules. [108][109][110] For example, AZO with a trans-form and SP with ring-closed forms can be converted to the corresponding cis-form and ring-open merocyanine form after exposure to UV light, respectively. This cis-form and merocyanine form are thermally unstable states.…”